Hypertensive disease has been shown to produce progressive pathological change in the vascular system, most particularly in the kidney, and in the heart. It is related closely also to the incidence of catastrophic events affecting the central nervous system which can alter suddenly the performance capabilities and social functioning of those patients who do survive. The experiments proposed are designed to investigate the possibility that blood pressure elevation in the hypertensive subject may lead to subtle deficits in the function of the central nervous system, quite apart from infarct or hemorrhage. We have described a series of selected behavioral tests of sensory/perceptual function, cognitive ability, psychomotor performance, and interpersonal nonverbal communication to assess the integrity of the central nervous system in groups of hypertensive patients and in age- and sex-matched normotensive controls. These studies will measure the effect of blood pressure elevation on CNS function and will help to elucidate the origins of the behavioral patterns which have been described in hypertensive subjects. Subsequent studies will be designed to determine the effects of antihypertensive therapies on such changes as may be observed.